Displacement compressor system for r-718

ABSTRACT

A displacement compressor system for the refrigerant R718 includes a compressor machine, an evaporator, and a condenser. The open compressor machine is designed as a spindle compressor in the form of a double-shaft rotation displacement compressor for displacing and compressing gaseous conveying media. The displacement compressor has a spindle rotor pair which is arranged in a compressor housing and is designed with an electronic motor pair spindle rotor synchronization function. The compressor machine is arranged between the evaporator and the condenser.

TECHNICAL FIELD

The refrigeration market is currently in flux and everyone is thustalking about the so-called “F-Gas Regulation” according to Regulation(EC) No. 842/2006 and No. 517/2014 on fluorinated greenhouse gases as achallenge, in order to roll back the predominant refrigerants HFC andHFO on account of their harmfulness for the climate and environment.There is thus a strong desire in the field of refrigeration technologyfor natural refrigerants, wherein in particular water stands out as aresult of its good thermodynamic characteristics.

BACKGROUND

The widespread implementation of water as refrigerant R-718 (=water)has, however, foundered on the fact that, for example compared toammonia in the same role, a displacement volume flow that isapproximately 300 times greater is necessary for the same performance.As the pressure ratio that is ideally above a factor of 10 is quitehigh, the demands on a compressor increase tremendously, which mustsimultaneously still be oil-free and has to work as efficiently aspossible under negative pressure, namely between 6 mbar and 200 mbarand, if necessary, still higher.

The disruptive character of water as a refrigerant is uncontested andwill abruptly end the discussions conducted intensively world-wideregarding the known environmental and climatic problems with currentrefrigerants. Refrigeration technology can be represented via two broadareas here:

-   -   mobile refrigeration/air-conditioning technology (i.e. for        trains, trucks and passenger cars)    -   stationary refrigeration technology (i.e. industrial        refrigeration, commercial refrigeration and building        air-conditioning, heat pumps)

Up to now, it has been attempted to meet this challenge withturbo-compressors, although these machines only generate lower pressureratios of approximately 6 despite their two-stage configuration withintermediate cooling so that the necessary heat transfer at thecondenser is realized merely to an unsatisfactory degree in the coolingcircuit. In addition, there is with a turbomachine the seriousdisadvantage of its soft working characteristic (i.e. pressure valuesabove volume flow) in order to be able to ensure stable operating pointsfor various operating points.

A displacement machine for water-vapour compression is without questionthe better solution in order to overcome the challenges of water-vapourcompression in R718 refrigeration circuits. For the compression of watervapour as refrigerant R-718, the following serious challenges must beresolved:

-   -   Conveyance of high water-vapour volume flows of well over 5.000        m³/h for, for instance, 35 kW refrigerating performance, which        is 60 times greater than in the prior art. Consequently, new        ground will have to be broken with respect to rotational speed        as well as the geometrical design of the displacement machine.    -   Control of large pressure ratios of well over 10 in the event of        low evaporator temperatures and higher temperatures in the        condenser. As the isentropic exponent in the case of water        vapour is simultaneously greater than 1.32 (present refrigerants        have an exponent of approximately 1.1 and are thus hardly        temperature-stressed), final compression temperatures of well        over 200° C. result mathematically for refrigerants R-718, said        temperatures only adversely affecting the effectiveness of the        compressor, but also posing a risk in particular to the        sensitive structural components of the compressor (especially        the rotor mount on the outlet side).    -   The refrigerant circuit must be completely oil-free for R-718        (=water vapour), which represents a challenge in the case of        twin-shaft displacement machines, because this type of machine        requires, if an operating fluid (these days mostly oil) is        omitted, a dry synchronisation for the spindle-rotor pair in        order to avoid contact between the quickly rotating spindle        rotors.

SUMMARY

The R718 displacement compressor system provides the followingadvantages:

(1) Safe avoidance of the consumption of play in the compressor:

-   -   The consumption of play in a compressor leads to its breakdown        as a so-called “crash” by the contact of the working-space        structural components, the gap values between the working-space        structural components being reduced from the standard millimetre        fractions to zero, even if not all over, but only where the        mostly thermal expansions combined with rotational errors and        other deviations among the variety of diverse influencing        parameters can lead to the same. Such a consumption of play is        to be avoided, by means of a sufficient safety margin for        absolutely all operational, working and ambient conditions at        all times in a reliable and complete manner.

(2) Best possible efficiency, i.e. optimum effectiveness for the R718displacement compressor system:

-   -   Besides the operation with optimally adapted operational        parameters, this relates in particular to the minimization of        the system losses and in this context primarily the impact of        inner gap leakages, which adversely affect efficiency, without        jeopardizing the imperative goal of crash avoidance.

(3) Greatest reliability and high durability (long service life) of theR718 system:

-   -   In this context, it is primarily the sensitive structural        components that need to be protected, in particular the rotor        mount (especially on the outlet side) and the two drive motors        with their respective equipment

(4) To the greatest possible extent *∘* independently of the externaloperating conditions in the sense that the R718 displacement compressorsystem adapts to the most varied conditions in an autonomous manner.

*∘* to the greatest possible extent in that there are practically norestrictions in said operating conditions.

(5) System intelligence:

-   -   The R718 displacement compressor system must be able, at all        times and in all circumstances, to achieve the aforementioned        advantages or, in the event of impending deviations, initiate in        a timely manner corrective measures including the emission of        external warnings and indications, in an autonomous manner by        means of its own regulating mechanisms and regulating tools.

This object of compressing water vapour at pressures below atmosphericpressure by means of a twin-shaft rotary displacement machine isachieved in accordance with the disclosure by configuring the R718displacement compressor system (42) as a closed vacuum system,comprising the core elements:

-   -   Evaporator (7) with evaporator housing vessel (29)    -   Condenser (8) with condenser housing vessel (28)    -   and compressor machine (41),        wherein this compressor machine essentially comprises:    -   Compressor housing (1)    -   two autonomous rotary units (39 and 40) with electronic        synchronization of the motor pair/spindle rotors via the FUs        (2.4 and 3.4) by means of the FU control unit (16)    -   and bearing support unit(s) (25) on the side of the outlet for        receiving the rotary bearing (4.2), and the outlet (12) with        outlet openings via control balls (10) as well as end outlet        openings (27)        and everything is managed by the control unit (15).

The compressor machine (41) is configured here in accordance with thedisclosure as an open machine that separates the evaporator (7) and thecondenser (8) by means of the compressor housing (1). The compressormachine thus no longer has face-side compressor-limiting lateral parts(so-called “covers”) and can no longer be operated in an autarkic manneras a vacuum machine but rather only in conjunction with a connectedevaporator (7) and a connected condenser (8) with respective housingvessels (28 and 29).

Moreover, the drive motors (2.3 and 3.3) for each spindle-rotor rotationunit (40 and 39) are located on the compressor inlet side (11) andsuspended directly in the evaporator chamber (7) for optimal cooling ofthe electric drive motors (2.3 and 3.3) for the “unlimited” operation inaccordance with the disclosure by purging the heat losses of these drivemotors (2.3 and 3.3) via the respective refrigerant fluid flows K5 inthe event of increased (i.e. above the nominal load) performance demandsduring operation. The monitoring of the drive motors (2.3 and 3.3)preferably occurs via temperature sensors in the area of the motorwindings in order to be able to adapt the respective refrigerant fluidflows K5 accordingly so that the drive motors are not damaged and canprovide the performance demanded.

Moreover, an intermediate water jacket (5), preferably with its owncooling tube coil (6), is part of this thermal balance management systemaccording to the disclosure for the R718 displacement compressor systemin order to operate the selective thermostatic control for thecompressor housing (1) via the refrigerant fluid flow K1. While theselective interior cooling of the rotors (2.2 and 3.2) by means of arefrigerant fluid flow K2 and K3 (as 9.2 and 9.3) remains simultaneouslypossible, the situation with respect to the play between theworking-space structural components (i.e. compressor housing andspindle-rotor pair) is regulated, and via the inner gap leakage thus thevolumetric efficiency for the different operating/working points as aresult of the respective thermal expansion behaviours of the structuralcomponents (which is saved in the control unit (15) for the regulationof the refrigerant fluid flows (9)), while crashes are simultaneouslyreliably avoided (crash as a disruptive consumption of play).

In order to implement the “unlimited” operation with simultaneousoptimum efficiency and reliable crash avoidance, the thermal balancemanagement according to the disclosure for the R718 displacementcompressor system in the “maximum” version*∘* comprises the followingrefrigerant fluid flows (9) regulated in a selective manner via controlunit (15):

-   -   9.1 Refrigerant fluid flow (illustrated as K1) to the        intermediate water jacket (5) via cooling tube coil (6)    -   9.2 Refrigerant fluid flow (illustrated as K2) to the 2t rotor        (2) via evaporator cooling bore (2.2)    -   9.3 Refrigerant fluid flow (illustrated as K3) to the 3t rotor        (3) via evaporator cooling bore (3.2)    -   9.4 Refrigerant fluid flow (illustrated as K4) for injection        cooling via centrifugal disk (22)    -   9.5 Refrigerant fluid flow (illustrated as K5) for the cooling        of each drive motor    -   *∘* Those applications pertain to the “maximum” version that        have a particularly large scope of application, i.e. when the        so-called “temperature lift” (as the difference between t_(c)        and t_(o)) is greater than approximately 40 Kelvin, wherein        smaller machines (i.e. with a displacement volume flow under        approximately 5.000 m³/h at a nominal speed) are less sensitive        here, i.e. higher “temperature lifts” are managed more smoothly.

This thermal balance management system is crucially necessary inparticular for the working-space structural components during so-calledk₀ operation, when the compressor is operated at a speed that, althoughcreating the difference in pressure between the inlet and the outlet,does not yet convey or only conveys a minimum volume flow, as a resultof which the compressor thus only contends with its own (interior)leakage, but would become accordingly hot on account of the powerinjection, which is reliably avoided by the thermal balance managementsystem managed by the control unit (15) in accordance with thedisclosure.

By means of this thermal balance management system which is practicallyindependent of external conditions, the aforementioned “unlimited”operation is achieved in accordance with the disclosure, because thecompressor machine (41) simultaneously achieves practically any pressureratio and thus practically any pressure value with the correspondingtemperature in the condenser in order to be able to purge the heatquantity in practically all surrounding conditions. This is theso-called “unlimited” operation, which does not exist in the prior art.Mentioned as an example here are the breakdowns of the air-conditioningsystems in ICE trains that occurred because their air-conditioningsystems could not handle the high outside temperatures. This can nolonger happen with the solution in accordance with the disclosure.

Furthermore, a centrifugal disk (22) is preferably arranged on everyspindle rotor on the gas inlet side (11) in accordance with thedisclosure for the speed-optimized introduction of the injectionrefrigerant quantity K4, wherein the refrigerant-fluid-flow-K4 feedaccording to (23.1) or (23.2) on the preferably rough surface of thecentrifugal disk ensures a speed-optimized refrigerant-fluid-flow-K4mist, which is mixed with the gas flow in a sufficiently even manner.“Speed-optimized” is understood to mean here that the velocity vectorsof the liquid refrigerant-fluid-flow-K4 mist droplets move similarly tothe spindle-rotor surfaces, which is ensured by each centrifugal disk(22). A hard impact on the spindle-rotor surfaces as a result of largedifferences in velocity, and consequently at the least an unpleasantpatter noise up to the damage of the spindle-rotor surfaces, isconsequently reliably avoided.

In addition, there is a tooth flank offset Δk_(vs)(z) in thelongitudinal rotor-axis direction z between the left and the rightprofile flank side so that the head angle be.2K(z) at the two-toothedspindle-rotor head arc becomes the be.2K.em(z) distribution inaccordance with the disclosure, whereas the be.2K.stu(z) distributionresults for selected distributions for μ.2(z) and μ.3(z) with acorresponding tooth height h(z) when there is no tooth flank offset. Byrepresenting the difference between be.2K.em(z) and be.2K.stu(z) asΔ.be.2K(z) distribution in conjunction with the pitch distribution m(z)and the distribution of the tooth heights h(z) in the longitudinalrotor-axis direction, it is evident that both the be.2K.em(z)distribution as well as the Δ.be.2K(z) distribution, put in a simplifiedmanner, are configured as the opposite of the pitch distribution m(z):

If m(z) is at a maximum, both the be.2K.em(z) distribution as well asthe Δ.be.2K(z) distribution are at a minimum. And if m(z) increases,both the be.2K.em(z) distribution as well as the Δn.be.2K(z)distribution decrease, whereas, in the event of a sharply decreasingm(z) in the inlet area, both the be.2K.em(z) distribution as well as theΔ.be.2K(z) distribution increase sharply. This feature according to thedisclosure is valid with a precision of preferably ±15% and ensures onthe inlet side (11), i.e. for the area of larger z values in the form ofrepresentation chosen here, higher volumes of the working chambers onthe inlet side in order to consequently be able to suction largerdisplacement volume flows.

To this end, values above 0.6 (for example 10% to 15% higher) in theinlet area of the compressor machine (41) are also proposed for μ.3(z)so that the suction volumes increase further.

DESCRIPTION OF THE DRAWINGS

Furthermore, control balls (10) are provided for the selectiveadaptation of the inner compression ratios in accordance with thespecific application, i.e. in particular in the event of differentpressure values in the condenser as different working points during theoperation of the R718 displacement compressor system. The inner volumeratio is, initially without taking thermodynamic effects into account,dependent on the geometry of the configured spindle-rotor pair as thesimple ratio of the inlet working-chamber volume to the outletworking-chamber volume, which is determined at the time of manufactureof the spindle-rotor pairing. As various operating points with differentpressure ratios (as outlet pressure p₂ divided by the inlet pressure p₁)are required, the control balls (10) ensure that efficiency-reducingovercompression is avoided in that the control ball is raised as aresult of the pressure difference when the current outlet pressure p₂ isreached in the particular working chamber during compression, so that apartial gas flow leaves the working chamber in the direction of theoutlet space (12) and thus to the condenser (8). This preferably occursboth in the longitudinal direction of the rotor axis as well as on theface side at the outlet end (12) in accordance with the illustrativerepresentation represented in FIG. 2. The control balls (10), which arepreferably weight-loaded, are raised by the difference in pressurebetween the current pressure in the particular working chamber and theoutlet pressure p₂ and move back by the force of gravity, which is shownby means of the angles in accordance with the illustrativerepresentation in FIG. 8, wherein g indicates the direction of gravity.Alternatively, it is of course also possible to implement a simplespring engagement for the control balls.

The control balls (10) in FIG. 1 and in FIG. 4 can be seen on the outletside in the outlet control disk (12) as well as in FIG. 2 in thelongitudinal direction of the rotor axis for the Π_(iV) adjustment foravoiding efficiency-damaging over- and undercompression as well as in anaxial top view in the outlet control disk (12) and adapt the so-calledinner volume ratio Π_(iV) in accordance with the specific application tothe particular pressure ratio actually present.

Moreover, an intermediate support (17) on the two-toothed spindle rotor(2) is proposed for weight reduction, in particular also as a lower massmoment of inertia during initial acceleration (as well as deceleration)with simultaneous high flexural rigidity, for example made of avacuum-compatible fibre-composite material, e.g. as a CFRP material.

Furthermore, there will generally be different application scenarioswith various temperature-lift application ranges with various “volumecurves” (i.e. the distribution of the working-chamber volumes betweeninlet and outlet in the longitudinal direction of the rotor axis) asvarious application-specific requirements so that various spindle-rotorpair designs in particular with respect to an energy-efficient mode ofoperation are also advantageous and useful. In order to avoid having tocompletely configure each compressor machine individually, it isproposed in accordance with the disclosure that various spindle-rotorpairings can be inserted in the practically identical*∘*∘ compressorhousing shown illustratively in FIG. 13. This is designated as “rotorconstruction kit” and means that, for various application scenarios, theindividually most efficient adaptation to the particular userrequirements is achieved in an uncomplicated manner by means of a simpleand direct changing of the spindle-rotor pair.

-   -   *∘* By “practically identical” it is understood that, for        example, the crossing angle α (shown in in FIG. 13) remains the        same, while the rotor length and possibly also the diametric        distribution in the longitudinal direction of the rotor axis can        vary while the compressor housing sleeve remains identical, the        simple and rapid implementation of various volume curves via        different spindle-rotor pairs being the core function of the        “rotor construction kit”. The simple and flexible manufacture of        the spindle rotors (generally by turning) is an important        feature here for a simple realization.

The inner volume ratio (i.e. the simple quotient of the working-chambervolume at the inlet divided by the working-chamber volume at the outlet)of the spindle-rotor pair is limited to an iV range preferably between 2up to a maximum of 20, wherein the adaptation to the particularworking/operating point with its current actual pressure ratios occursvia the aforementioned control balls (10) in accordance with thespecific application. If still greater temperature lifts ΔT_(h) inaccordance with

ΔT _(h) =t _(c) −t ₀

with correspondingly higher pressure ratios are necessary, mostlymomentarily, during operation, a so-called undercompression occurs (thepressure of the last working chamber is lower than the pressure at theoutlet) and the last working chamber is pushed out in an isochoricmanner against a higher pressure at the outlet (12). In order to curbthis process which reduces the efficiency of the compressor, it isproposed in accordance with the disclosure that the play values in thecompressor outlet area are selectively increased by approximately 20 toat least 50% greater average gap clearances, preferably realized simplyin that the outer rotor diameters are manufactured to be correspondinglysmaller over an area in the longitudinal direction of the rotor axiscorresponding to 0.3 to 2 times the extension of the working-chamberlength on the outlet side in the longitudinal direction of the rotoraxis, wherein, in the event of a face-side outlet plate with a bearingsupport (25) on the control edge (27.S), this is also realized bybevelling (in the sense of rendering oblique) said control edge (27.S).

These measures in accordance with the disclosure combined with thesimultaneous limitation of the inner-volume ratio range at thespindle-rotor pair, preferably to the aforementioned iV range, arecalled

-   -   “outlet-gap-iV adaptation”.

The outer rotor diameter/gap adaptation on the rotor pair preferablyoccurs here so that this diametric adaptation, which progresses in thedirection of the outlet initially slowly, increases to progressivelylarger values so that the averaged gap clearances reach theabove-mentioned increase as an average. This outlet-gap-iV adaptationhelps in particular to reduce noise as the pressure pulsations on theoutlet side are dampened.

For good measure, the “PIRSA” procedure is proposed for the R718displacement compressor system (42) with its respective spindle-rotorpairs, preferably for every working/operating point: “PIRSA” stands for“Pressure/Inner Ratio/Speed Adaptation”. It is known that variousworking/operating points can be realized by means of different operatingparameters (mentioned illustratively in the following). By means of“PIRSA”, the operating parameters are adjusted via the control unit (15)so that the power input for the R718 displacement compressor system (42)is minimal for the particular working/operating point required inaccordance with the specific application.

As operating parameters, this is especially valid regarding:

-   -   Regulation of the refrigerant fluid flows (9) in particular with        regard to the injection quantity (9.4)    -   Adaptation of the spindle-rotor speeds via the CU-FU (16) for a        certain suction capacity    -   Setting of the pressure values in the evaporator (8) and in the        condenser (9)

The control unit (15) has its own preinstalled databank here and canadapt these operating parameters in a regulating manner, wherein thisprocess occurs through self-learning by means of trial and error inaccordance with the specific application, by modifying individual valuesslightly and determining by the reaction of the system whether theoverall efficiency improved or suffered. This way, the databank isconstantly broadened in every operating point through self-learning andthe system becomes increasingly more intelligent in terms of efficiencyimprovement.

Brief explanation regarding the tooth flank offset ΔkVs(z) for eachprofile flank side:

or every rotational angle position φ, there is, corresponding to thetransmission ratio for each spindle rotor, a z-position as az(φ)-function, the derivation of which via the equation below thenyields the so-called pitch distribution m(φ) for each spindle rotor,wherein a distinction is additionally made in accordance with thedisclosure between the right and the left profile flank side via theindex s:

$\begin{matrix}{{m_{s}(\phi)} = {{2{\pi \cdot \frac{{dz}_{s}(\phi)}{d\; \phi}}} \approx {2{\pi \cdot \frac{\Delta \; {z_{s}(\phi)}}{\Delta \; \phi}}}}} & \;\end{matrix}$

As the distinction between the right and left profile flank side isdifficult and often leads to confusion with regard to the perspective aswell as its dependence on the pitch direction (i.e. right- orleft-handed) for each rotor, the tooth flank offset according to thedisclosure is illustrated via the head arc angle be.2K(z) in accordancewith FIG. 9 in a simplified manner in the plane, although this type ofproblem is three-dimensional due to the non-parallel rotational axes ofthe spindle rotors.

Brief explanation regarding the formation of the tooth profile:(simplified as a plane representation)

The various tooth heights h(z) in the longitudinal direction of therotor axis (generally designated by z) are generated via the so-called μvalues at each rotor, as the following equations are valid for the tipradii for each spindle rotor:

on the 2t rotor:

R _(2K)(z)=μ₂(z)·a(z)  (Eq. 1.1)

on the 3rotor:

R _(3K)(z)=μ₃(z)·a(z)  (Eq. 1.2)

Accordingly, the following equation is valid in the longitudinalrotor-axis direction z for the tooth height h(z):

h(z)=(μ₂(z)+μ₃(z)−1)·a(z)  (Eq. 1.3)

The distributions for μ.2(z) and μ.3(z) are preferably chosen so thatthe requirements of the specific application are fulfilled to thehighest possible degree, for example with respect to working-chambervolume as well as the so-called “volume curve” (i.e. the distribution ofthe working-chamber volumes in the longitudinal direction of the rotoraxis, wherein in particular the variation of these working-chambervolumes is of importance). The following holds for μ.3(z) here:

-   -   For, μ₃(z)≤0.6 the pairing of the 2rotor (2) and the 3t rotor        (3) remains without a blowhole.    -   In order to increase the working-chamber volume on the inlet        side, it can be useful for some applications to increase the        μ.3(z) value above this value of 0.6.    -   The μ.2(z) value can be chosen freely, although, besides the        tooth heights h(z), the remaining base circle thicknesses are of        importance, with the objective that the critical bending speeds        for each spindle rotor are realized in accordance with:

$\begin{matrix}\underset{\begin{matrix}\underset{2 \cdot {rotor}}{Critical} & \underset{3 \cdot {rotor}}{Critical}\end{matrix}}{{\omega_{\underset{2 \cdot {Rotor}}{kritisch}} = 1},{5 \cdot \omega_{\underset{2 \cdot {Rotor}}{kritisch}}}} & \underset{\underset{y\mspace{14mu} {critical}}{Generall}}{\omega_{\underset{allgemein}{kritisch}} = \sqrt{\frac{c}{m}}}\end{matrix}\mspace{14mu} {with}\mspace{14mu} ({simplified})$

-   -    In particular via the values for μ.2(z) and μ.3(z) as well as        regarding the rotor length and the rotor masses, the critical        bending speed of the faster-rotating 2t rotor (3) is realized        1.5 times higher than with the 3t rotor (3).

With these points, the aforementioned advantages are achieved by way ofthe present disclosure:

The thermal balances of the working-space structural components, i.e.the housing (1) and the spindle-rotor pair (2 and 3), in the R718displacement compressor system (42) are managed and regulated so thatthe following advantages are simultaneously met at all times and in allconditions and intelligently by the system:

-   -   (1) Safe avoidance of play consumption (so-called “crash” by        contact of the working-space structural components) due to the        fact that, for the different operating/working points, the        various thermal expansions of the working-space structural        components work with measured reference-temperature values by        means of the intelligent management of the thermal balances with        expansion behaviours of the working-space structural components        saved in the control unit (15) for the different temperature        levels at each operating/working point.    -   (2) Minimization of inner gap leakage by observance of a gap        range, preferably in a range of ±25%, wherein the lower value is        derived from the avoidance of gap consumption plus a safety        margin and lies in the range of 0.05 to 0.1 mm with a        corresponding rotational precision of preferably less than 0.02        mm for machine sizes with a range of axle-separation distances        of approximately 100 mm to approximately 500 mm (below this, the        value is correspondingly smaller; above, larger)    -   (3) Protection of the sensitive structural components, in        particular the rotor mount (especially on the outlet side) and        the two drive motors by means of the described purge-gas system        (30 and 31)    -   (4) To the greatest possible extent*∘* independently of external        conditions of application in the sense that the R718        displacement compressor system adapts to the most varied        conditions in an autonomous manner. *∘* to the greatest possible        extent so that there are practically no restrictions regarding        conditions of application.

(5) Intelligent management via the control unit (15), in particular ofthe refrigerant fluid flows as well as in accordance with PIRSA so thatthe R718 displacement compressor system has the respectively lowestenergy requirement in every operating point, i.e. works with thegreatest efficiency and simultaneously achieves the aforementionedadvantages.

The necessary capability for accomplishing these advantages inaccordance with the disclosure in the sense of intelligence lies in thecontrol unit (15). Both its design as well as its operation must beconfigured in accordance with the disclosure so that the advantagesmentioned in the introduction are reliably achieved at all times.

In order to meet these advantages, the following regulating variablesare available:

-   -   K1. Housing thermal-balance management    -   K2. 2t spindle-rotor thermal-balance management    -   K3. 3t spindle-rotor thermal-balance management    -   K4. Injection for evaporation cooling during the compression        process    -   K5. Cooling of the motors

The speed adaptation occurs via FUs (2.4 and 3.4) via the electronicsynchronization of the motor pair/spindle rotors by means of the FU-CU(16) in conjunction with the control unit (15).

CET stands for Compressor End Temperature=i.e. the temperature at thegas outlet of the compressor

The injection cooling K4 performs the main share of cooling duringcompression, whereas the cooling of the working-space structuralcomponents is added by the control unit (15) in particular to compensatefor various thermal expansions of each working-space structuralcomponent and/or to protect the sensitive structural components (inparticular the rotor mount as well as the drive motors) by saving thisin the algorithm of the control unit (15).

Evaporator (7) with the (lower) pressure p₁ and the temperature t₀before the displacement compressor machine

Condenser (8) with the (higher) pressure p₂ and the temperature t_(c)after the displacement compressor machine, which compresses therefrigerant R-718 from p₁ to p₂, wherein the refrigerant R-718 undergoesthe temperature increase from t₀ to t_(c).

Fundamental Explanation

The cooling water “Kü” generally purges the heat Q_(ab) from thecondenser (8), while the heat Q_(ent) is withdrawn from the chilledwater “Ka” in the evaporator (7) by the displacement compressor system.

Designated as the refrigerant (abbreviated as “K”) here is the waterthat is diverted from the evaporator (7) as a refrigerant fluid flow ina manner regulated by the control unit (15) in the refrigerant separator(26) for separation into a main flow HS and the individual refrigerantfluid flows K1, K2, K3, K4 and K5 for the achievement of theaforementioned advantages.

(1) The heat balance for the compressor housing (1) is selectively setin accordance with the disclosure as the so-called “housingthermal-balance management” via the intermediate water jacket (5) by thecontrol unit (15) in accordance with the specific application as set outbelow:

-   -   a) cooled via external cooling water “Kü” in the intermediate        water jacket (5) when the control unit (15) determines from the        actually present temperature values (in particular for “Kü”) in        comparison with those stored in the databank in the control unit        (15) that the available cooling water temperatures in accordance        with the specific application are favourable (in most cases in        the sense of low enough) for the housing thermal balance in        order to institute play settings between the compressor housing        (1) and the spindle-rotor pair (2 and 3) which, first, avoid a        crash (as play consumption) reliably while, second, ensuring the        optimum efficiency of the compression with respect to inner gap        leakage, specifically: The gap values for crash avoidance lie in        the range of 0.03 to 0.05 mm, a safety margin (for example        because of rotational deviations) of approximately 30% to 50%        being added so that the lower gap values result, designated as        ΔSp.u. The upper gap values ΔSp.o should preferably not be        greater than ΔSp.u by a factor higher than 2.    -    By means of the various thermal expansion behaviours of the        working-space structural components (i.e. essentially the        housing and the rotor pair), the so-called thermal-balance        management system now has to maintain, via the refrigerant fluid        flows (9) regulated by the control unit (15), the actual gap        values between ΔSp.0 and ΔSp.o in accordance with the specific        application.    -   b) If the cooling water temperatures available in accordance        with the specific application are unfavourable (in most cases in        the sense of too high) for the housing thermal balance, then the        control unit (15) ensures via the refrigerant fluid flow 9.1        (illustrated as K1), for example by means of a regulation organ        (26) and simple cooling pipe coil (6) in particular in the        outlet area, that the rising heat in the intermediate water        jacket (5) is purged, wherein rising in the sense of the        extension in the longitudinal rotor-axis direction depending on        the convection in the intermediate water jacket as the        intermediate medium carrier and compensation of temperature        differences that are too high.

(2) unlimited through internal cooling during operation independently ofexternal conditions and self-adjusting, i.e. at 5° C. ambient conditionsas well as at 60° C.=indication of limits no longer necessary=thecondenser temperature is automatically increased and the inner coolingadapts automatically, i.e. no more requirements regarding max.admissible cooling water temperature=in accordance with the disclosure,everything is now feasible

(3) in particular the e-motors can be overloaded practically at willthanks to the adaptable intensive cooling

(4) Intermediate water jacket (5) on the compressor housing (1) withinsulation jacket (20) toward the condenser (8)

(5) Compressor with open inlet (11) and outlet (12), there are no longerany lateral housing end parts (“covers”), it is no longer a classicallyautarkic compressor, but rather an open machine

(6) Cooling mechanisms diverted and distributed by the control unit asso-called “working-space structural-component thermal managementsystem”:

-   -   HS is the main flow for achieving the basic object between heat        absorption in the evaporator and the release of heat in the        condenser    -   K1 Cooling for the compressor housing, preferably as evaporator        cooling via intermediate water jacket (also only so much that        the resulting gap values via the minimized rotor cooling K2 and        K remain in a selected range, e.g. preferably within ±25%)    -   K2 Structural-component cooling for the two-toothed spindle        rotor→minimized(!) primarily for the protection of the bearings    -   K3 Structural-component cooling for the three-toothed spindle        rotor→minimized(!) primarily for the protection of the bearings    -   K4 Cooling by refrigerant injection→bears the brunt as the most        important variable, i.e. >80%    -   K5 Cooling for each drive motor→only for the maintenance of        operation (monitored & managed by the motor thermal elements,        preferably in the motor coils)

(7) Structural-component cooling K1 and K2 and K3 for the implementationof two main requirements:

-   -   Command of the play settings in order to be able to compensate        for various thermal expansions, wherein the play values should        preferably remain within approximately ±25%.    -   command of k₀ operation as well as minimum displacement volume        flows in a reliable and sustained manner    -   Avoidance of temperatures that are too high for critical        structural components, in particular bearings on the outlet side

(8) Injection K4 as the main cooling mechanism by means of evaporationduring the compression

-   -   Objective: fine mist as largest possible surface for efficient        evaporation as heat transfer during compression    -   Centrifugal disks with rough surface and terminal inclination        for the avoidance of streamlets, for a distribution as even as        possible    -   Centrifugal disk with outer groove, if appropriate with radial        drainage bores, in order to reduce slippage    -   Feed to the centrifugal disk or, if appropriate, as drainage        bore in the bottom via double tube or via the support arm for        the suction bearing support    -   Injection instead of centrifugal disk via bores in the bottom at        the inlet (unlikely)    -   Use of injection as regulation of the actual inner compression:        The evaporating liquid causes a sharp volume increase in the        working chamber with corresponding increase in pressure

(9) The distance between the spindle-rotor axes at the inlet (11)preferably at least 10% greater than at the outlet (12)

(10) Adaptation of the inner volume ratio Π_(iV) via vacuum-compatiblecontrol balls (10), which are preferably weight-loaded and pushed asideby the difference in gas pressure and also return by the force ofgravity to a (preferably elastomer) ramp (10.R) inclined at the angleγ_(R) when Δρ falls again, configured

-   -   over the rotor length (represented illustratively in FIG. 2)    -   as well as on the end plate (12) as control disk (represented        illustratively in FIG. 1)

(11) Outlet end plate as control disk (12) via peeling disks for theideal play adjustment for the face-side gap between the end of the rotorand the end plate individually for each spindle rotor

(12) The effort for the iV adaptation (e.g. via control balls) can bedrastically reduced in accordance with the specific application by theadjustment of the respective pressure values both at the condenser aswell as at the evaporator with a simultaneous volume flow adaptation sothat the pressure ratio of these two pressure values corresponds to theinner volume ratio Π_(iV) of the compressor so that an over- orundercompression is kept within acceptable limits avoided in accordancewith PIRSA=Pressure/Inner Ratio/Speed Adaptation

(13) Pitch distribution via the tooth flank offset Δk_(vs)(z) variedbetween the right and left tooth flank for the maximization of thecross-sectional surface area in each end section in particular in thesuction area: As the right tooth flank in a 2t spindle rotor configuredas right-handed has the distribution vis-à-vis the left tooth flank thatis represented illustratively, the tooth width of the 2t spindle rotoris reduced for the purpose of maximizing the traverse-sectionworking-chamber scooping surface areas in the suction area designated astooth flank offset of the flanks in relation to one another inaccordance with the disclosure

(14) cylindrical inner cooling of spindle rotor can be limited to thelast area, i.e. not over the entire rotor length (with correspondingincrease in the bottom wall thickness at the inlet)

(15) the maximum version is represented (so to speak the “Mercedes”), asall cooling mechanisms are realized—there will also be a slimmed-downversion (so to speak the “VW”), by preferably/for example omitting thestructural-component cooling and adjusting the temperatures duringcompression only via the injection cooling, i.e.: the above advantagescan only be achieved in a limited manner, as this is sufficient forseveral applications.

(16) Drive motors on the inlet side (on account of constructional spaceas well as temperature protection with overload option)

(17) K₀ speed measurement (as self-diagnosis for the determination ofchanges, e.g. formation of deposits, etc.)

(18) CFRP intermediate support (17) on the two-toothed spindle rotor forweight reduction, in particular the mass moment of inertia when starting(accelerating) with simultaneously high flexural rigidity

(19) Configuration for purging via the intermediate spaces by means of abypass bore for each rotor mount

(20) Circumferential overflow groove in the evaporator and drain at thedeepest point for the operating modes according to FIG. 14 as analternative to the closed circuit with the riser pipe (19)

(21) Mixing tap and mixing section as option for selective temperatureadjustment

(22) preferably with CO2 cascade system for lower temperatures

FIG. 1 illustratively shows a representation of a longitudinal sectionthrough the R718 displacement compressor system (42) in accordance withthe disclosure with a standing configuration. The compressor machine(41) separates the evaporator (7) with the lower values for pressurep₁=p₀ and temperature t₀ from the condenser (8) with the higher valuesfor pressure p₂=p_(c) and temperature t_(c), each with a surrounding,vacuum-maintaining housing vessel (28 and 29), preferably cylindricaland fixed on the compressor-housing extension (1.P) in accordance withFIG. 5. The customary vacuum pump for ensuring negative pressure is notshown in the represented R718 displacement compressor system (42), butis sufficiently known and implemented in accordance with FIG. 4 whenpurging preferably via the shielding-gas discharge (31) shown in FIG. 4.

For a more detailed illustration, FIG. 3 shows an enlargement of theinlet area with the evaporator (7) of this representation and FIG. 4shows an enlargement of the outlet area with the condenser (8). Theimportant gap values between the rotor head and the housing are adjustedby means of peeling disks (18) on the inlet side via the positions ofthe spindle-rotor units (39 and 40 in accordance with FIG. 13) in thelongitudinal rotor-axis direction. Likewise, the face-side gap values ofthe spindle rotor to the outlet control disk (12) are adjusted viapeeling disks (18).

FIG. 2: As an illustrative sectional representation relating to FIG. 1perpendicular to the axis of the housing vessel (28) approximatelyhalfway down the longitudinal rotor axis in a perspective looking towardthe outlet (12) as a cylindrical cooling-system cross section for theR718-displacement compressor system with control balls (10) both in thelongitudinal rotor-axis direction (the control balls are accordinglyshown as sectioned and shaded) and as a top view of the outlet controldisk (12) simply as circular control-ball openings, which are shown inturn in FIG. 1 as sectioned and shaded at the outlet (12). Furthermore,the end outlet openings (27) with the control edges (27.S) can be seenclearly on the outlet control disk (12).

FIG. 3: As an illustrative representation for the suction area shown inFIG. 1 with a representation of the respective refrigerant fluid flowsK1 and K2 and K3 and K4 and K5 with HS as the circuit-medium-R718 mainflow for the achievement of the core objective for the transfer of heat.Besides the different possibilities for the refrigerant-fluid-flow feed,various configurations are shown simultaneously (in practice they arerealized separately) for the heat transfer in the evaporator (7), byhaving the refrigerant R-718 flow, for example, via the overflow groove(37) over a large enough surface to the drain (37.a) OR via separateheat-exchanger surfaces (38), for example as an embedded heat-exchangerpipe system (38) on the floor of the housing vessel (29) in order toensure the represented heat transfer Q_(ent) from the evaporationprocess. In order to minimize undesired heat transfers here, differentinsulation approaches (29.i) are represented, e.g. via an insulationlayer (left side in FIG. 3) or via an evacuated intermediate space(right side in FIG. 3).

FIG. 4: As an illustrative representation for the outlet area shown inFIG. 1 with a representation of the housing cooling system via theintermediate water jacket (5) with cooling pipe coil (6), moreovercontrol balls (10) in the outlet control disk (12) and a purge-gasapparatus for each shielding-gas feed (30) and discharge (31) via abuffer space (13) via the aforementioned vacuum pump creating suctionfor the desired negative pressure in the displacement compressor system,moreover illustratively with the regulating organ (26) for theseparation of the refrigerant fluid flows K1=1, K2=2, K3=3, K4=4, andK5=5 (designated as “KM-TS.Δ”) as well as HS=0 as circuit-medium-R718main flow (as “KM-HS”), said separation being regulated by the controlunit (15) in accordance with the specific application.

FIG. 5: As illustrative 3D representation toward the compressor housing(1) with separation between evaporator space and condenser space via thepreferably cylindrical dividing plate (1.P), moreover with thepreferably three attached bearing-support support arms (24) for eachbearing support (25). In this representation, the principle of the“open” compressor becomes clear, as merely the two spindle-rotorrotation units (39 and 40) are mounted in the housing, and thecompressor machine (41) is practically complete without specificface-side closing parts (thus “open” compressor)

FIG. 6: Illustratively represented is an enlargement of the feed (23.1)of injection refrigerant K4 to the centrifugal disk (22) via abearing-support support arm (24) in the compressor inlet area (11) shownin FIG. 1, by having the refrigerant fluid flow K4 reach, for examplevia a small tube, the upper side of the centrifugal disk (22), where K4,which is distributed evenly by means of centrifugal forces, then entersthe gas flow at the inlet (11) with the optimum speed profile vis-à-visthe spindle rotor.

FIG. 7: As an illustrative representation of the centrifugal disk (22)preferably with rough, course surface for the reduction of slippage andbetter distribution of the refrigerant fluid flow K4, wherein thediameter øa.s as well as the height h and the angle γ_(s) substantiallyinfluence the spray of the refrigerant fluid flow K4 from thecentrifugal disk and are to be configured in accordance with thespecific application.

FIG. 8: As an illustrative representation of the control ball (10) forthe adaptation of the inner volume ratios to various temperature liftswith corresponding pressure differences, rolling away on the ramp (10.R)via the angles γ_(A) and γ_(R) with respect to the direction of gravityg while preferably subject to the force of gravity by means of thedifference in pressure Δ_(p) at the control ball between the particularworking-chamber pressure and the outlet pressure, a special material notnecessarily being necessary here, and automatically rolling back byforce of gravity when the difference in pressure decreases.

FIG. 9: Illustrative representation of the spindle-rotor profilepairing, wherein the problem, which is actually three-dimensional onaccount of non-parallel rotational axes, is shown in a simplified mannerin a plane. As a section through the end of the spindle-rotor pairshowing the head arc angle be.2K(z), which yields the tooth flank offsetΔk_(vs)(z) as a different z(φ) distribution for the right and leftprofile flank for each tooth, as well as with the particular μ value foreach spindle rotor via the rotor head circles with a(z) distribution forthe distance between the rotor axles.

FIG. 10: When determining the rotor profile pairing, the followingfunctional distributions, illustratively for the crossing angle α=15°between the rotational axes of the rotor at a rotor profile length ofL=376 mm, are shown, which portray the tooth flank offset Δk_(vs)(z) viathe Δ.be.2K(z) distribution in relation to the pitch distribution m(z)in the longitudinal rotor-axis direction z, wherein this z progressionis always chosen as the abscissa, i.e. the value range: 0≤z≤L. Theoutlet (12) is at z=0 and the inlet (11) is at z=L here

FIG. 10.1: [Values Only Illustrative]

The correlation between the rotational-angle extension parameter φ forthe range 0°≤φ≤1320° and the z position as a z(φ) function yields thepitch distribution m(φ) via the known equation:

$\begin{matrix}{{m(\phi)} = {2{\pi \cdot \frac{{dz}(\phi)}{d\; \phi}}}} & \;\end{matrix}$

Applied over the longitudinal rotor-axis direction, the representedpitch distribution m(z) then results, which begins at z=0 mm with 28 mm,then quickly increases to a pronounced maximum range before the inlet(11), the pitch falling at z=L quickly back to 78 mm.

FIG. 10.2: [Values Only Illustrative]

The tooth height h(z) in the longitudinal rotor-axis direction resultsfor each axis separation-distance value a(z) in accordance with thecrossing angle via the meshing spindle-rotor heads, wherein therotor-head radius values then result via the respective μ values fromthe following equations:

R _(2K)(z)=μ₂(z)·a(z)

and

R _(3K)(z)=μ₃(z)·a(z)

and

h(z)=(μ₂(z)+μ₃(z)−1)·a(z)

The μ values shown in FIG. 10.2 lead here to the cylindrical rotor mountshown in FIG. 1 in order to make possible the evaporator cooling at eachspindle rotor in particular during k₀ operation.

FIG. 10.3: [Values Only Illustrative]

As a continuation of FIG. 10.2, two configurations relating to the μvalues shown for the head arc angle be.2K(z) on the two-toothed spindlerotor are represented:

-   -   In cases where there is no tooth flank offset between the right        and left profile flank side, the dashed-dotted be.2K.stu(z)        distribution results for the head arc angle, the distribution        falling continuously from 65° at z=0 to 53° at z=L.    -   The be.2K.em(z) distribution in accordance with the disclosure        starts at z=0 for example also at 65°, then exhibits a very        different distribution, as there is a minimum in the last third        of the rotor length on the inlet side, after which it then        increases rapidly to 70° at z=L.

FIG. 10.4: [Values Only Illustrative]

As the continuation of FIG. 10.3, instead of the p distributions, thepitch m(z) in accordance with FIG. 10.1 is now depicted and the oppositedistribution between be.2K.em(z) and m(z) is clearly visible

FIG. 10.5: [Values Only Illustrative]

Complementing FIGS. 10.3 and 10.4, the difference between be.2K.em(z)and be.2K.stu(z) as the Δ.be.2K(z) distribution is additionally depictedin conjunction with the pitch distribution m(z) so that the idea inaccordance with the disclosure with regard to the tooth flank offsetΔk_(vs)(z) between the left and the right profile flank side becomesclear.

FIG. 11: As an illustrative representation, three differentspindle-rotor pairs for the rotor construction kit are represented asFIG. 11.1 and FIG. 11.2 and FIG. 11.3, which fit with respect to theirouter/connecting geometry to the same compressor housing (1), at theleast to the same housing sleeve, wherein the following descriptionapplies:

FIG. 11.1 shows illustratively a spindle-rotor pair with a high suctioncapacity with a moderate number of tiers for applications in which it isless the compression capacity that is of importance, but a high volumeflow.

FIG. 11.2 shows illustratively a spindle-rotor pair with a moderatesuction capacity with an intermediate number of tiers for applicationswithout a pronounced prioritization, i.e. more of a general orientation.

FIG. 11.3 shows illustratively the spindle-rotor pair with a low suctioncapacity with a very high number of tiers for applications in which ahigh compression capacity is more important than volume flow.

FIG. 12.1: Illustrative representation of an alternative design for theoutlet control disk (12), in which control balls (10) can be omitted, byconfiguring the outlet control disk to be rotatable (12.S) together withthe pivot bearings (12.g) as well as the discharge slot (12.s) at theend of the two-toothed spindle rotor.

FIG. 12.2: Illustrative representation of the configuration of therotatable outlet control disk (12.d) with the discharge slot (12.s) aswell as, in addition, lateral outlet notches (12.k), so that the lastworking chamber pushing outward does not close again when the minimuminner compression ratio is adjusted. These notches are necessary becausethe discharge slot (12.s) cannot take up too much of the circle asotherwise the factor by which the inner compression can be increasedsinks. When the maximum inner compression ratio is set, the outletnotches (12.k) are above the chamber that would open without the outletcontrol disk (12.d). The outlet notches (12.k) are then closed laterallyby the outlet plate, which closes off the 3t spindle rotor, and thecompressor housing (1). Shortly before the last working chamber hascompletely emptied, the compressor housing (1) is laterally removed andthe 3t spindle rotor is open.

FIG. 13: Represented illustratively are the finished and completelybalanced spindle-rotor rotation units (39 and 40), which, withoutfurther intervention via the peeling disks (18), can be inserted withoutany changes in the compressor housing (1) for the exact gap adjustmentand thus form the open compressor machine (41).

FIG. 14: Represented illustratively are 3 operating modes for operatingthe R718 displacement compressor system for different cooling-water(“ü”) and chilled-water (“a”) temperature levels, which are optimallyset in accordance with the specific application by the control unit (15)by means of PIRSA as “Pressure/Inner Ratio/Speed Adaptation”, asdescribed.

Terms such as substantially, preferably, and the like as well aspossibly, as indications of imprecision, are to be understood in thesense that a deviation of plus/minus 5%, preferably plus/minus 2% andespecially plus/minus one percent from the standard value is possible.The applicant reserves the right to combine any features and also anysub-features from the claims and/or any features and also partialfeatures from a sentence of the description in any way with otherfeatures, sub-features or partial features, also beyond the features ofindependent claims.

In the different figures, parts that are equivalent with respect totheir function are always provided with the same references so thatthese are generally only described once.

In the displacement system for the refrigerant R718 with a compressormachine (41), an evaporator (35) and a condenser (36), the opencompressor machine (41) is configured as a spindle-rotor compressor inthe form of a twin-shaft rotary displacement machine for conveying andcompressing gaseous media. It has a spindle-rotor pair (2 and 3), whichis arranged in a compressor housing (1) and configured with anelectronic synchronization of the motor pair/spindle rotors. Thecompressor machine (41) is arranged between the evaporator (35) and thecondenser (36).

Terms such as substantially, preferably, and the like as well aspossibly, as indications of imprecision, are to be understood in thesense that a deviation of plus/minus 5%, preferably plus/minus 2% andespecially plus/minus one percent from the standard value is possible.The applicant reserves the right to combine any features and also anysub-features from the claims and/or any features and also partialfeatures from a sentence of the description in any way with otherfeatures, sub-features or partial features, also beyond the features ofindependent claims.

In the different figures, parts that are equivalent with respect totheir function are always provided with the same references so thatthese are generally only described once.

REFERENCE LIST

-   -   1. Compressor housing preferably simultaneously with ø-dividing        plate (1.P) between evaporator (7) and condenser (8) with a        distance between the spindle-rotor-receiving bores that is at        least 15% greater on the inlet side than on the outlet side,        wherein these bore axes are preferably configured so as to        intersect (i.e. with perpendicularity) or cross (i.e. skewed).    -   2. Spindle rotor, preferably with two-toothed gas-displacing        outer thread, called “2t rotor” for short, preferably comprising        an aluminium alloy with good thermal conductivity (preferably        over 150 W/m/K), rotationally fixed via brace points on a steel        shaft (2.1) with a cylindrical evaporator cooling bore (2.2)        oriented inward and driven directly on the inlet side by its own        drive motor (2.3) controlled by its own frequency converter        (2.4), designated as “FU.2”, and by an FU control unit as        “FU-CU” (16) via electronic motor-pair/spindle-rotor        synchronization    -   3. Spindle rotor, preferably with three-toothed gas-displacing        outer thread, called “3t rotor” for short, preferably comprising        an aluminium alloy with good thermal conductivity (preferably        over 150 W/m/K), rotationally fixed via brace points on a steel        shaft (3.1) with a cylindrical evaporator cooling bore (3.2)        oriented inward and driven directly on the inlet side by its own        drive motor (3.3) controlled by its own frequency converter        (3.4), designated as “FU.3”, and by an FU control unit as        “FU-CU” (16) via electronic motor-pair/spindle-rotor        synchronization    -   4. Mount for each spindle rotor, which is mounted at both ends,        preferably configured on the inlet side as a fixed bearing (4.1)        for axial and radial forces and on the outlet side as a floating        bearing (4.2) which is preferably engaged in a cushioning manner    -   5. Intermediate water jacket for regulation of the thermal        balance for the compressor housing (1) with external thermal        insulation (20) toward the surrounding condenser (8)    -   6. Cooling pipe coil in the intermediate water jacket, which is        preferably guided so as to be closer together on the outlet side        and ends toward the evaporator (7)    -   7. Evaporator with the (lower) pressure p₁−p₀ and the        temperature t₀ before the compressor machine (41)    -   8. Condenser with the (higher) pressure p₂=p_(c) and the        temperature t_(c) after the compressor machine (41), which        compresses the refrigerant R-718 from the pressure p₁ to p₂,        wherein the refrigerant R-718 fundamentally undergoes the        temperature increase from t₀ to t_(c).    -   9. Respective refrigerant fluid flows for complete management,        regulated by the control unit (15), of the thermal balances of        the working-space structural components, i.e. housing and rotor        pair, as well as for the compression process as defined below:    -   9.1 Refrigerant fluid flow (illustrated as K1) to the        intermediate water jacket (5) via cooling pipe coil (6)    -   9.2 Refrigerant fluid flow (illustrated as K2) to the 2t rotor        (2) via evaporator cooling bore (2.2)    -   9.3 Refrigerant fluid flow (illustrated as K3) to the 3t rotor        (3) via evaporator cooling bore (3.2)    -   9.4 Refrigerant fluid flow (illustrated as K4) for injection        cooling via centrifugal disk (22)    -   9.5 Refrigerant fluid flow (illustrated as K5) for the cooling        of each drive motor    -   9.6 The circuit medium-R718 main flow for achieving the core        object for the heat transfer (e.g. as heat pump, or in the        refrigeration technology process) is represented as HS.    -   10. Control balls that are vacuum-compatible for the adaptation        of the inner volume ratio Π_(iV) for various working points for        the avoidance of an efficiency-reducing over- or        undercompression both in the longitudinal rotor-axis direction        as well as for each control disk (12) in accordance with the        desired field of application with a ramp (10.R) inclined at an        angle γ_(R) vis-à-vis the direction of gravity “g” in accordance        with FIG. 8    -   11. Gas inlet as open collection space for the medium with the        gas pressure p₀ (for simplification, pressure losses in the        lines are neglected for the time being)    -   12. Gas outlet as a control disk for each spindle rotor with        defined outlet openings for the medium at the gas pressure p_(c)        (for simplification, pressure losses in the lines are neglected        for the time being)    -   13. Neutral collection/buffer space for each working-space shaft        passage with reduced gas pressure vis-à-vis the system pressure,        preferably created e.g. by means of a negative-pressure/vacuum        pump in order, as a “purge-suction chamber”, to be able to purge        the rotor bearings, if necessary, i.e. protect by inert gas,        wherein this inert gas is fed from outside for each bearing        position, then passes these bearings via a bypass bore and is        again suctioned off at this collection/buffer space.    -   14. Synchronization gearing as mechanical fall-back safe-guard        for the electronic synchronization of the motor pair/spindle        rotors, for example in the event of a power failure according to        an operation by generator    -   15. Control unit CU as control and regulation unit with        evaluation of the particular current measurement values and        output on this basis of the regulating signals for the        intelligent operation of the spindle compressor with links and        data preferably stored in the CU memory as well as continuously        learning dependencies between the respective measurement values        received and the gap values according to a previous simulation,        verification and continuous experiences, the control unit is        connected to FU-CU (24) as well as, on the side of the user, to        process control technology for its application system as well as        industrial control system in the sense of “Industry 4.0”    -   16. FU control unit, designated as “FU-CU”, for the two        frequency converters FU.2 (2.4) and FU.3 (3.4), wherein FU-CU        exchanges the data regarding the operation of the spindle        compressor directly with the control unit (15).    -   17. Intermediate support on the two-toothed spindle rotor (2)        with minimal thickness (below 2.5 g/cm³) yet high flexural        rigidity, preferably as fibre composite material, e.g. CFRP        vacuum-compatible    -   18. Distance/spacer disks, preferably configured as so-called        “peeling disks”, for the individual fixation of each spindle        rotor in the longitudinal direction of the rotor axis for the        selective adjustment of the gap value as Δ2.1 value on the 2t        rotor (2) and as Δ3.1 value on the 3t rotor (3)    -   19. Pressure-reducing organ in the closed internal circuit, for        example via the utilization of the geodetic difference in        altitude in a water tower, i.e. use of gravity for pressure        reduction    -   20. Thermal insulation for the intermediate water jacket (5)    -   21. Angled rest for the control balls    -   22. Centrifugal disk (preferably with rough/course surface) for        feeding and fine distribution of the refrigerant fluid flow into        the suction area (11) of the compressor according to K4 as        injection cooling    -   23. Feed of the refrigerant fluid flow K4 to the centrifugal        disk (22), wherein this feed can be configured in accordance        with one's wishes as:    -   23.1 Feed of the refrigerant fluid flow K4 via a cantilever (24)        of the bearing supports (25) 23.2 Feed of the refrigerant fluid        flow K4 via the central bore in each rotor support shaft (2.1        and 3.1)    -   24. Cantilever of the bearing support, preferably 3 for each        bearing support (25), fluidically advantageous    -   25. Bearing support for receiving the rotor bearings (4),        simultaneously face-side chamber delimitation on the outlet side    -   26. Regulating organ for the separation of the refrigerant fluid        flows (9) managed by the control unit (15)    -   27. End outlet openings with control edge (27.S) for each rotor        after the control balls (10) as of a value regarding the inner        volume ratio iV predetermined in accordance with the specific        application    -   28. Vacuum-compatible condenser housing vessel on the housing        ø-dividing plate (1.P), attached in a horizontal position and        sealed; in the case of a vertical operation, the condenser        housing vessel is erect    -   29. Vacuum-compatile evaporator housing vessel preferably        attached on the housing ø-dividing plate (1.P) with insulation        (29.i, illustrated as cross hatching or as an intermediate        vacuum space) for ensuring the efficient Q_(ent) thermal        balance; in the case of vertical operation, the evaporator        housing vessel is located at the bottom    -   30. Shielding-gas feed (so-called “purging”) for the protection        of the bearings (4) as well as, if appropriate, of the drive        units so that said areas to be protected constantly have a        slightly (a few mbar of differential pressure, e.g. 3 to 10        mbar, are sufficient) higher pressure than the immediate        R718-water-vapour surroundings; as inert/shielding gas, normal        air will be sufficient in most applications, although, for        example, nitrogen can also be selected    -   31. Shielding-gas discharge generated via a separate vacuum        backing pump, which preferably also ensures the vacuum system        pressure. With this shielding-gas discharge system, a certain        R718-water-vapour partial flow is also suctioned off via the        working-space shaft seal so that this R718 loss must be re-fed        to the system as water. As a seal for the reduction of this R718        water-vapour-loss partial flow, the flow resistance of the        working-space shaft seal should be increased, for example via a        brush seal    -   32. Bearing-bypass bore for avoiding a gas flow through the        mount (4)    -   33. Feed of the refrigerant fluid flow for the cooling of the        rotor interior for each spindle rotor as:    -   33.1 Feed pipe in the central bore of each spindle-rotor support        shaft    -   33.2 Feeding of the refrigerant fluid flow K2 for the cooling of        the interior of the 2t rotor via feed pipe (33.1)    -   33.3 Feeding of the refrigerant fluid flow K3 for the cooling of        the interior of the 3t rotor via feed pipe (33.1)    -   34. Retainer bushing in central support-shaft bore to stop the        refrigerant fluid from flowing off    -   35. Symbol for the condenser according to the disclosure in        accordance with FIG. 1    -   36. Heat exchanger    -   36.ü Heat exchanger on the cooling water side    -   36.a Heat exchanger on the chilled water side    -   37. Circumferential overflow groove in the evaporator for        supplied evaporation water with drain (37.a) in the event of a        mode of operation according to FIG. 13, wherein this draining        water then becomes refrigerant fluid flow (9)    -   38. Heat exchanger (e.g. as pipe system) for heat transfer        Q_(ent) lying on the inner side in the evaporator (7)    -   39. Spindle-rotor rotation unit for the three-toothed        spindle-rotor system    -   40. Spindle-rotor rotation unit for the two-toothed        spindle-rotor system    -   41. (Complete) compressor machine as open twin-shaft rotary        displacement machine    -   42. (Complete) R718 displacement compressor system

1. An R718 displacement compressor system comprising a compressormachine, an evaporator, and a condenser, wherein the compressor machineis configured as a spindle compressor formed as a twin-shaft rotarydisplacement machine configured for conveying and compressing gaseousmedia, includes a spindle-rotor pair in a compressor housing, with anelectronic synchronization of the motor pair/spindle rotors, and isarranged between the evaporator and the condenser.
 2. The R718displacement compression system according to claim 1, wherein thespindle compressor respectively includes one for each spindle rotor, inthat two drive motors are arranged on a side of a gas inlet of thespindle compressor and project with their entire circumference into aspace of an evaporator, configured for sufficiently discharging thermalpower losses.
 3. The R718 displacement compressor system according toclaim 1, wherein the system further includes a purge system via ashielding-gas supply feed and a shielding-gas discharge, configured toprotect a plurality of sensitive structural components.
 4. The systemaccording to claim 1, further comprises a centrifugal disk provided oneach spindle rotor which introduces the injection cooling amount intothe gas flow on the gas inlet side.
 5. The R718 displacement compressorsystem according to claim 1 wherein the two spindle rotors havedisplacement profile flanks which are configured with a tooth profileoffset Δk_(vs)(z) between the right and the left profile flank side,wherein the tooth flank offset is preferably represented and generatedvia the Δ.be.2K(z) distribution in relation to the pitch distributionm(z) in the longitudinal rotor-axis direction z.
 6. The R718displacement compressor system according to claim 1 wherein it alsoincludes control balls, which preferably take on the selected adaptationof the inner compression ratios in accordance with the specificapplication.
 7. The R718 displacement compressor system according toclaim 5 wherein the two-toothed spindle rotor is provided with anintermediate support, by which means preferably a weight reduction, inparticular also for a lower mass moment of inertia during initialacceleration and deceleration, is achieved with a simultaneous highflexural rigidity, for example made from vacuum-compatible fibrecomposite material, e.g. as a CFRP material.
 8. The R718 displacementcompressor system according to claim 1 wherein at least onerefrigerant-fluid feed is provided, in that each spindle rotor has acylindrical evaporator cooling bore, which is connected to therefrigerant-fluid feed.
 9. The R718 displacement compressor systemaccording to claim 8 wherein each drive has a hollow shaft, in that therefrigerant-fluid feed to the cylindrical evaporator cooling bore ofeach drive occurs through the hollow shaft, and the bearings areconfigured for life.
 10. The R718 displacement compressor systemaccording to claim 1 wherein the system further includes anoutlet-gap-iV adaptation, by means of which undercompression is curbed.11. A spindle compressor disposed in the R718 displacement compressorsystem according to claim 1 wherein the spindle compressor has a controlunit, which optimizes by means of the control of the operatingparameters the efficiency of the R718 displacement compressor system inevery working/operating point by means of the control unit.